Remove k256 crate from frame-support dependencies (#14452)

* Add test for to_eth_address

* Replace k256 with secp256k1

* Bump Cargo.lock

* Reformat

Author: conr2d

Cargo.lock

@@ -298,7 +298,6 @@ hash-db = { opt-level = 3 }
 hmac = { opt-level = 3 }
 httparse = { opt-level = 3 }
 integer-sqrt = { opt-level = 3 }
-k256 = { opt-level = 3 }
 keccak = { opt-level = 3 }
 libm = { opt-level = 3 }
 librocksdb-sys = { opt-level = 3 }